Practical session 8: Finish retesting and explain the limits

Mentor Teaching · Teacher directions · 15 October 2026

Plan and prerequisites

50–65 minutes; add supervised continuation for delays or repeats. Planning estimate; adjust to the class.

Accurate decimal °C/time reading; calculate change; measure 150 mL; follow the matched-pair and probe-position procedure. Carry forward the preceding session evidence. The adult must check the current complete operational guide, equipment and room/water conditions before handling. Bring the original/redesign versions, retained proposal, first-phase records, R1 and the pre-phase instrument check.

Print in this order

1. Practical retest: directions, instrument checks and trials 2–3

2. Practical results: reassess and explain

Give each independent or new-evidence file only at the stage described below. Keep answers with the teacher.

Teach and demonstrate

Recheck current room/water/equipment conditions after any continuation break. Complete fresh R2 and R3 against the original sleeve using the printed order: R2 original right/B and redesign left/A; R3 original left/A and redesign right/B. Follow the response wait, volume/start checks, 0/5/10 readings and 5-minute conditioning/reset; retain all departures.

Learner work and evidence

Complete the post-phase instrument check. Compare all three retests and the first phase without silently merging conditions from different days. Give the separate Reassess and explain pages. Collect raw readings, a bounded result, a reasoned revision and a useful next test. Worse, negligible, mixed and inconclusive results are legitimate.

Next decision and continuation

Flag mismatch, drift, missing readings or wet/changed sleeves as the procedure requires. Clean up with the teacher. If safe equipment/conditions are unavailable, use the separate supplied-data Part 1 then Part 2 and identify the work as fictional-record analysis; it does not replace missing measured results or demonstrate construction/testing. Keep the later reasoning assessment reserved.

Matching complete teacher key

Use the current complete operational guide’s retest, reassessment and explanation keys. The later reasoning check is a separate later task, not part of today’s primary handout.

Open the matching complete teacher guide

Access and interpretation

Offer oral, dictated, pointing or labelled responses when they show the same intended reasoning. Keep each task’s quantities, conditions and sources available. Allow extra response paper. A supplied-data explanation does not establish actual construction or testing.